Thesis (BEd)-- Stellenbosch University, 1944 / Stellenbosch University. Faculty of Education. Dept. of Educational Psychology. / ENGLISH ABSTRACT: Activities such as throwing are, as a rule, carried out only with the better arm. Mostly this one-sided execution is due to mere convenience. If attempts are made to justify it, in the main two arguments are advanced: In the first place, it is taken for granted that the inferior arm cannot make appreciable progress anyway, and it is therefore considered as not worthwhile exercising it. In the second place, it is believed that, if the inferior arm should improve by such a practice, this happens at the expense of efficiency in general, and may have detrimental consequences in some regards or other. / AFRIKAANSE OPSOMMING: geen opsomming

D.Litt. et Phil. / Hypertension amongst older adults is one of the highest indices of prevalence in the general population, both in the United States and in South Africa. Due to this high 'indices in South Africa, it has. a tendency to develop into malignant hypertension, resulting in high indices of morbidity and mortality. Seniors South Africans, mainly Black South Africans (more than elsewhere in the world), face severe indices of morbidity and mortality as a result of uncontrolled, untreated or poorly treated hypertension. For this reason, the HELPS Project (Hypertension, Exercise and Lifestyle Program for Seniors) at San Diego State University was replicated in the South African context to determine wbetherit would show similar differential effects. The initial findings of this study suggest that exercise and physical activity has a significant effect on blood pressure in elderly hypertensives. There was a lowering of blood pressure, as well as reduction in some of the antihypertensive medication. The results indicated that all forms of exercise tend to lower blood pressure in older hypertensives. Very little difference was noted between groups who did only stretching and calisthenics exercise, slow walking, or brisk aerobic walking. This was attributed to a so-called "threshold effect" by the projectleader Dr J. Martin. The results of this study was in keeping with the findings of the HELPS (San Diego) Project. The study proved that both aerobic and anaerobic exercise alike provide elderly people with benefits in both physiological and psychological aspects of functioning. More specifically, where drug therapy may cause health risks and negative side effects, exerciseoften leads to overall benefits and enhances quality of life in the elderly. The overall results of the study was generally upheld and in keeping with the proposed hypotheses

Acute aerobic exercise exerts a small beneficial effect on cognition. Much of the research to date has focused on cognitive changes following a bout of exercise, while little is currently known about changes in cognitive performance during exercise. The limited research that has been conducted suggests either positive, negative, or no effects on cognitive performance during exercise. Thus, the primary purpose of this study was to examine the effects of low-intensity cycling on cognitive function in college-aged students, indexed by response accuracy, reaction time, P3 amplitude, and P3 latency. Twenty-seven (Mage = 22.9 ± 3.0 years old) college-aged individuals were counterbalanced into low-intensity exercise (EX) and seated control (SC) conditions. During each condition, participants completed a 10-minute resting baseline period, 20 minutes of either sustained cycling or seated rest, and a 20-minute recovery period. Primary outcomes were assessed at 10-minute intervals (5 blocks total) throughout each condition via a modified oddball task. Across time blocks, both conditions exhibited faster reaction times on frequent trials but reduced accuracy to rare trials, suggesting a speed-accuracy tradeoff. There were no differences between conditions in P3 latency whereas a significant reduction in P3 amplitude was observed during the 20-minute exercise period compared to the control condition. Taken together, the results suggest that exercise at lower doses may have minimal influence on behavioral outcomes of cognitive performance but may impact more basic measures of brain function. Information gathered from this study may aid in the development of appropriate exercise prescriptions for populations looking to specifically target cognitive function deficits.

Despite extensive research into shift work, workers working under rotating shift conditions are still plagued by the effects of the desynchronisation resulting from working against their natural circadian rhythms. Additionally, modern industries are shifting towards tasks requiring greater cognitive demand with less manual labour incorporated into the tasks. Research into operator based tasks, and hence those of a sedentary cognitive base both during day and night shifts, has been focusing on the effectiveness of the standard rest/break schedule. Research indicating that the standard rest break schedule is often ineffective in eliminating operator discomfort and performance deterioration, with these affects argued to be more pronounced during a night shift schedule. Therefore current research set out to investigate alternative rest break schedules, incorporating a short bout of physical activity and stretching exercises which are proposed to enhance performance and subjective mood, while eliminating operator discomfort for sedentary based cognitive tasks. Three conditions were tested during a three day habituation shift cycle within a laboratory, incorporating two night shift groups (control and experimental) and a control day shift group. Twelve subjects made up each group, with the two night shift groups completing the shift schedule together. The control groups followed a typical 8 hour shift schedule while the experimental group performed a booster break (exercise and stretches) activity for 7.5 minutes every hour during the night shift schedule. Over the course of the shift, subjects completed a battery of six tests providing data on physiological measurements (heart rate and temperature), performance criteria (reaction time responses, memory and neurobiological) and subjective measures. Responses obtained for all the different parameters measured indicated a strong circadian influence for the majority of the variables, indicating the course of natural down regulation within physiological and performance criteria over the night shift. The booster break significantly improved reaction time performance, subjective ratings and resulted in a high sustainable activity level. Day shift comparisons indicating that within subjective measures and reaction time performance, the booster break resulted in similar responses to those of the day shift workers, while the control night shift groups reported significantly lowers results. Additionally, the booster break had positive influences during the circadian nadir, significantly improving parameters of performance and subjective ratings of sleepiness. The results of this study indicating which variables are strong predictors and indicators of the oscillations in performance and subjective ratings due to the circadian changes. The booster break interventions had positive effects on subjective ratings and reaction time performance, while also being argued to decrease the burden placed on the cardiac system as a result of increased sympathetic tone during the night shift, while additionally resulting in similar responses to those of day shift workers. Further studies are required, however, to provide conclusive evidence particularly within a working situation over a longer shift schedule.

Cardiovascular activities may increase the brain blood flow improving neuronal activities leading to improved cognition. Consequently, the effects of an acute bout of moderate intensity aerobic exercise on brain hemodynamics and its correlation with cognitive color-word Stroop task performance were tested. The Stroop tasks were congruent (color matches word) and incongruent (color does not match word). Prefrontal (PFC) and motor cortex (MC) blood flow was recorded by fNIRS (functional near-infrared spectroscopy) while the subject was performing the Stroop tasks before and after the 30 minutes of exercise or equivalent time of rest controls (checking for practice effects). Ninety human subjects of age 24± 6, 20 ADHD (attention-deficit hyper-activity disorder), 27 High-BMI (>25), 29 males were recruited. Reaction time ‘RT' decreased (p<0.05) after exercise for both the congruent (12%) and incongruent (10%) Stroop tasks, compared to 8% with practice alone. Accuracy did not change after practice or exercise. HR changes after exercise correlated (p<0.05) with better accuracy and faster RT for the incongruent Stroop task. In general, a metabolic lag occurred in the neuronal deoxy- hemoglobin (Hb) signals behind the systemic oxy-Hb signals. PFC showed the highest effect sizes of Stroop task-responsive systemic hemodynamic changes compared to baseline irrespective of rest or exercise. Yet, PFC showed most significant (p<0.001) neuronal hemodynamic changes between the before and after exercise sessions, and these changes were opposite for right and left PFC, and opposite for congruent and incongruent Stroop tasks. Correlating the RT and mistakes with hemodynamics for both the Stroop tasks revealed that, after exercise, neuronal hemodynamic changes occurred at both PFC and MC associated with faster RT (p<0.05), and systemic hemodynamic responses occurred at PFC correlated (p<0.05) with mistakes. Overall, it was concluded that exercise changed the neuronal hemodynamic changes affecting speed; however, neuronal metabolic changes did not occur sufficiently to help improve accuracy in all subjects.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Research objective To test a novel concept that exposing patients with fibromyalgia syndrome (FMS) to visuals of exercise activities elicits neurophysiological changes in functional brain areas associated with pain catastrophization; thereby providing preliminary support for the further development/testing of a virtual reality exposure therapy (VRET) exercise program aimed at reducing pain catastrophization toward exercise therapy in patients with FMS. Methods The main study of this research consisted of a three-phase exploratory fMRI study. Phase 1 involved the development/validation of the fMRI visual task. Phase 2 involved the exploration of the differences in neural correlates associated with pain catastrophizing between participants with FMS and healthy controls when exposed to various visuals of exercise and passive/relaxing activities. Phase 3 involved the testing of the preliminary efficacy of a novel VRET exercise program on pain catastrophization in participants with FMS. The fMRI task consisted of two stimuli: active (exercise activity visuals)/passive (relaxing activity visuals). Structural images as well as blood-oxygenation-level-dependent (BOLD) contrasts were acquired for the conditions and compared within-subjects/groups and between-groups. The condition of interest was the active>passive condition (where brain activations for the passive condition were subtracted from the active condition). The brain volumes collected during ‗on‘ conditions were compared with the brain volumes collected during ‗off‘ conditions using Students‘ t test. Statistic images were thresholded using clusters determined by Z>2.3 and a (corrected) cluster significance threshold of p=0.05. Results The right (R) middle and inferior frontal gyrus and R posterior cerebellum were significantly activated for the participants with FMS, and not the healthy control group, during the active>passive condition (phase 2). At baseline, during the active>passive condition (phase 3), the intervention/VRET group showed significant activation (p<0.05) in the R insular cortex, R anterior and posterior cerebellum, R parahippocampal gyrus, R middle frontal gyrus, R corpus callosum, R thalamus, R supramarginal gyrus and R middle and superior temporal gyrus; the control group showed significant activation in the R anterior and posterior cerebellum, R middle and superior temporal gyrus, R middle frontal gyrus, R insular cortex, R supramarginal gyrus and R precentral gyrus. Post-intervention, during the active>passive condition, R posterior cerebellum activation was still significant (p<0.05) for the intervention group; R anterior cerebellum, left (L) middle and inferior frontal gyrus, and R superior parietal lobe activation was found to be significant (p<0.000) for the control group, although these areas were not found to be significantly activated at baseline for the control group. Conclusion We could not provide confirmatory evidence for the efficacy of a novel VRET program for pain catastrophization in patients with FMS. However, the findings of this study does suggest that pain catastrophization in patients with FMS could be confirmed with fMRI. Research is therefore warranted to further develop a proper VRET exercise program and to test the effect of this program on pain catastrophization in patients with FMS. / AFRIKAANSE OPSOMMING: Navorsing doelstelling Om 'n nuwe konsep dat die blootstelling van pasiënte met fibromialgie sindroom (FMS) aan beeldmateriaal van oefening, ontlok neurofisiologiese veranderinge in funksionele brein-areas wat verband hou met pyn katastrofering te toets; sodoende voorlopige steun vir die verdere ontwikkeling/toetsing van 'n virtuele realiteit blootstelling terapie (VRET) oefenprogram wat gemik is op die vermindering van pyn katastrofering na oefenterapie in pasiënte met die FMS te bied. Metodes Die hoofstudie van hierdie navorsing bestaan uit 'n drie-fase verkennende fMRI studie. Fase 1 het die ontwikkeling/validering van die fMRI visuele taak behels. Fase 2 het die ondersoek van die verskille in die neurale korrelate geassosieer met pyn katastrofering tussen deelnemers met FMS en gesonde kontroles wanneer hulle blootgestel word aan verskeie beeldmateriaal van oefening en passiewe/ontspannende aktiwiteite behels. Fase 3 het die toets van die voorlopige effektiwiteit van 'n nuwe VRET oefenprogram op pyn katastrofering in deelnemers met FMS behels. Die fMRI taak het bestaan uit twee stimuli: aktiewe (oefening aktiwiteit beeldmateriaal)/passiewe (ontspannende aktiwiteit beeldmateriaal). Strukturele beelde sowel as bloed-suurstof-vlak-afhanklike (BSVA) kontraste is vir die toestande verkry en vergelyk binne-deelnemers/groepe en tussen-groepe. Die toestand van belang was die aktiewe>passiewe toestand (waar brein aktivering vir die passiewe toestand afgetrek is van die aktiewe toestand). Die brein volumes wat ingesamel tydens die 'aan' toestande is vergelyk met die brein volumes wat ingesamel is gedurende die 'af' toestande met die gebruik van Studente se t-toets. Drempel statistiek beelde is gegroepeer deur Z> 2,3 en 'n (gekorrigeerde) groepeerde betekenisvolle drempel van p = 0.05. Resultate Die regter (R) middel- en inferior-frontale gyrus en R posterior serebellum is betekenisvol geaktiveer vir die deelnemers met FMS, maar nie vir die gesonde kontrole groep nie, gedurende die aktiewe>passiewe toestand (fase 2). By basislyn, tydens die aktiewe>passiewe toestand (fase 3), die intervensie / VRET groep het betekenisvolle aktivering (p <0.05) in die R insulaire korteks, R anterior en posterior serebellum, R para- hippokampus gyrus, R middel-frontale gyrus, R korpus kallosum, R talamus, R supramarginale gyrus en R middel- en superior-temporale gyrus; die kontrole groep het betekenisvolle aktivering in die R anterior en posterior serebellum, R middel- en superior-temporale gyrus, R middel-frontale gyrus, R insulaire korteks, R supramarginale gyrus en R presentrale gyrus. Post-intervensie, tydens die aktiewe>passiewe toestand, was R posterior serebellum aktivering betekenisvol (p <0.05) vir die intervensie groep; R anterior serebellum, links (L) middel- en inferior-frontale gyrus en R superior pariëtale lob aktivering was betekenisvol (p <0.000) vir die kontrole groep, alhoewel geen betekenisvolle basislyn aktivering in hierdie areas by die kontrole groep plaasgevind het nie. Gevolgtrekking Ons kan nie bewyse vir die effektiwiteit van 'n nuwe VRET program vir pyn katastrofering in pasiënte met FMS bevestig nie. Nietemin, dui die bevindinge van hierdie studie wel daarop dat pyn katastrofering in pasiënte met FMS bevestig kon word met fMRI. Verdere navorsing is dus geregverdig om 'n behoorlike VRET oefenprogram te ontwikkel en die uitwerking van hierdie program op pyn katastrofering in pasiënte met FMS te toets.

Thesis (PhD (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Background: There has been a dramatic increase in the use of dietary creatine supplementation among sports men and women, and by clinicians as a therapeutic agent in muscular and neurological diseases. The effects of creatine have been studied extensively in skeletal muscle, but knowledge of its myocardial effects is limited. Objectives: To investigate the effects of dietary creatine supplementation with and without exercise on 1) basal cardiac function, 2) susceptibility to ischaemia/reperfusion injury and 3) myocardial protein expression and phosphorylation and 4) mitochondrial oxidative function. Methods: Male Wistar rats were randomly divided into control or creatine supplemented groups. Half of each group was exercise trained by swimming for a period of 8 weeks, 5 days per week. At the end of the 8 weeks the open field test was performed and blood corticosterone levels were measured by RIA to determine whether the swim training protocol had any effects on stress levels of the rats. Afterwards hearts were excised and either freeze-clamped for biochemical and molecular analysis or perfused on the isolated heart perfusion system to assess function and tolerance to ischaemia and reperfusion. Five series of experiments were performed: (i) Mechanical function was documented before and after 20 minutes global ischaemia using the work heart model, (ii) A H2O filled balloon connected to a pressure transducer was inserted into the left ventricle to measure LVDP and ischaemic contracture in the Langendorff model, (iii) The left coronary artery was ligated for 35 minutes and infarct size determined after 30 minutes of reperfusion by conventional TTC staining methods. (iv) Mitochondrial oxidative capacity was quantified. (v) High pressure liquid chromatography (HPLC) and Western Blot analysis were performed on blood and heart tissue for determination of high energy phosphates and protein expression and phosphorylation. Results: Neither the behavioural studies nor the corticosterone levels showed any evidence of stress in the groups investigated. Hearts from creatine supplemented sedentary (33.5 ± 4.5%), creatine supplemented exercised rats (18.22 ± 6.2%) as well as control exercised rats (26.1 ± 5.9%) had poorer aortic output recoveries than the sedentary control group (55.9 ± 4.35% p < 0.01) and there was also greater ischaemic contracture in the creatine supplemented exercised group compared to the sedentary control group (10.4 ± 4.23 mmHg vs 31.63 ± 4.74 mmHg). There were no differences in either infarct size or in mitochondrial oxygen consumption between the groups. HPLC analysis revealed elevated phosphocreatine content (44.51 ±14.65 vs 8.19 ±4.93 nmol/gram wet weight, p < 0.05) as well as elevated ATP levels (781.1 ±58.82 vs 482.1 ±75.86 nmol/gram wet weight, p<0.05) in blood from creatine supplemented vs control sedentary rats. These high energy phosphate elevations were not evident in heart tissue and creatine tranporter expression was not altered by creatine supplementation. GLUT4 and phosphorylated AMPK and PKB/Akt were all significantly higher in the creatine supplemented exercised hearts compared to the control sedentary hearts. Conclusion: This study suggests that creatine supplementation has no effects on basal cardiac function but reduces myocardial tolerance to ischaemia in hearts from exercise trained animals by increasing the ischaemic contracture and decreasing reperfusion aortic output. Exercise training alone also significantly decreased aortic output recovery. However, the exact mechanisms for these adverse myocardial effects are unknown and need further investigation. / AFRIKAANSE OPSOMMING: Agtergrond: Die gebruik van kreatien as dieetaanvulling het in die afgelope aantal jaar dramaties toegeneem onder sportlui, sowel as mediese praktisyns wat dit as ‘n terapeutiese middel vir die behandeling van spier- en neurologiese siektes aanwend. Die effekte van kreatien op skeletspier is reeds deeglik ondersoek, maar inligting aangaande die miokardiale effekte van die preperaat is beperk. Doelwitte: Om die effekte van kreatien dieetaanvulling met of sonder oefening ten opsigte van die volgende aspekte te ondersoek: 1) basislyn miokardiale funksie, 2) vatbaarheid vir iskemie/herperfusie besering, 3) proteïenuitdrukking en -fosforilering in die miokardium en 4) mitochondriale oksidatiewe funksie. Metodes: Manlike Wistar rotte is ewekansig in kontrole of kreatien aanvullings groepe verdeel. Helfte van elke groep is aan oefening in die vorm van swemsessies, vir ‘n periode van 8 weke, 5 dae per week blootgestel. Gedrags- en biochemiese toetse is aangewend om die moontlike effek van die swemprotokol op die rotte se stres vlakke te bepaal. In hierdie verband is die oop area toets gebruik, asook bloed kortikosteroon vlakke gemeet deur radioaktiewe immuunessais. Harte is daarna uit die rotte gedissekteer en gevriesklamp vir biochemiese en molekulêre analise, of geperfuseer op die geïsoleerde werkhart perfusiesisteem om sodoende funksie en weerstand teen iskemie en herperfusie beskadeging te bepaal. Vyf eksperimentele reekse is uitgevoer: (i) Meganiese funksie is noteer voor en na 20 minute globale isgemie in die werkhart model; (ii) ‘n Water gevulde plastiek ballon, gekoppel aan ‘n druk omsetter, is in die linker ventrikel geplaas om sodoende linker ventrikulêre ontwikkelde druk (LVDP), asook iskemiese kontraktuur te meet; (iii) Linker koronêre arterie afbinding is vir ‘n periode van 35 minute toegepas en die infarktgrootte bepaal na 30 minute herperfusie deur gebruik te maak van standaard kleuringsmetodes; (iv) Mitochondriale oksidatiewe kapasiteit is gemeet; (v) Hoë druk vloeistof chromatografie (HPLC) en Western Blot analises is uitgevoer op bloed en hartweefsel vir die bepaling van hoë energie fosfate (HEFe), sowel as proteïenuitdrukking en -fosforilering. Resultate: Beide gedragsstudies en kortikosteroonvlakke het geen teken van stres in die betrokke groepe getoon nie. Die groep blootgestel aan kreatienaanvulling en oefening se harte het na iskemie funksioneel swakker herstel as harte van die onaktiewe kontrole groep (18.22±6.2% vs 55.9±4.35%; p<0.01), asook ‘n groter ikgemiese kontraktuur in vergelyking met die onaktiewe kontrole groep ontwikkel (31.63±4.74 mmHg vs 10.4±4.23 mmHg). Daar was geen verskille in infarktgrootte of mitochondriale suurstofverbruik tussen die verskillende groepe waargeneem nie. HPLC analise het verhoogde fosfokreatien (44.51±14.65 vs 8.19±4.93 nmol/gram nat gewig, p<0.05) en adenosientrifosfaat (ATP) bloedvlakke (781.1±58.82 vs 482.1±75.86 nmol/gram nat gewig, p<0.05) in kreatien aanvullings vergelyk met die kontrole groepe getoon. Daar was egter geen meetbare veranderings in HEF vlakke in hartweefsel nie. Gepaardgaande hiermee het kreatienaanvulling geen effek gehad op die uitdrukking va die kreatien transporter nie. In vergelyking met onaktiewe kontrole harte was GLUT4, en fosforileerde AMPK en PKB/ Akt beduidend hoër in harte van geoefende rotte met kreatienaangevulling. Gevolgtrekking: Hierdie data dui daarop dat kreatienaanvulling geen effek op basislyn miokardiale funksie het nie. Kreatienaanvulling het egter die miokardium se weerstand teen iskemiese skade verlaag in harte van rotte blootgestel aan oefening: iskemiese kontraktuur is verhoog en aorta-uitset tydens herperfusie is verlaag. Die presiese meganismes hierby betrokke is egter onbekend en vereis dus verdere studie. / Division of Medical Physiology (University of Stellenbosch), The National Research Foundation and the Harry Crossley Fund for financial support.

<p>The primary aim of this study was to investigate the changes in physical fitness characteristics of elite women&rsquo / s rugby union players over the duration of the season. Thirty two elite female rugby players who were identified as members of the South African Rugby Union High Performance Squad were assessed on three separate occasions (pre-season, mid-season and post-season) throughout the competition season. The players were sub-divided into two positional categories consisting of 17 forwards and 15 backs. On all testing occasions, players underwent anthropometric (stature, body mass and sum of 7 skinfolds) and physical performance measurements (sit-and-reach, vertical jump, 10m and 40m speed, 1 RM bench press / pull-ups / 1 min push-ups and multi-stage shuttle run test). A two&ndash / factor analysis of variance evaluated differences in the physical fitness variables between and within playing positions over the competition season.</p>

<p>The primary aim of this study was to investigate the changes in physical fitness characteristics of elite women&rsquo / s rugby union players over the duration of the season. Thirty two elite female rugby players who were identified as members of the South African Rugby Union High Performance Squad were assessed on three separate occasions (pre-season, mid-season and post-season) throughout the competition season. The players were sub-divided into two positional categories consisting of 17 forwards and 15 backs. On all testing occasions, players underwent anthropometric (stature, body mass and sum of 7 skinfolds) and physical performance measurements (sit-and-reach, vertical jump, 10m and 40m speed, 1 RM bench press / pull-ups / 1 min push-ups and multi-stage shuttle run test). A two&ndash / factor analysis of variance evaluated differences in the physical fitness variables between and within playing positions over the competition season.</p>

Magister Artium (Sport, Recreation and Exercise Science) - MA(SRES) / The primary aim of this study was to investigate the changes in physical fitness characteristics of elite women's rugby union players over the duration of the season. Thirty two elite female rugby players who were identified as members of the South African Rugby Union High Performance Squad were assessed on three separate occasions (pre-season, mid-season and post-season) throughout the competition season. The players were sub-divided into two positional categories consisting of 17 forwards and 15 backs. On all testing occasions, players underwent anthropometric (stature, body mass and sum of 7 skinfolds) and physical performance measurements (sit-and-reach, vertical jump, 10m and 40m speed, 1 RM bench press; pull-ups;1 min push-ups and multi-stage shuttle run test). A two-factor analysis of variance evaluated differences in the physical fitness variables between and within playing positions over the competition season. / South Africa